Principal features of this invention are shown in Disclosure Document No. 132,925 filed Dec. 3, 1984.
This invention relates to traffic control systems wherein means are provided to separate adjacent lanes of a roadway to facilitate movement of traffic in opposite directions. Generally, two-way roadways are marked with a center stripe or provided with a median barrier to provide an equal number of traffic lanes available to flow of traffic in each direction. This is satisfactory during most periods but it is highly desirable to be able to increase the number of traffic lanes to accommodate the increased flow of traffic in one direction or the other during peak commuting hours in urban areas. One system, commonly used, involves the placement of hollow cones or tubular cylinders along lane dividers to provide a more visible separator between lanes wherein traffic flows in opposite directions. Such separators must be moved one at a time and before and after each peak traffic period and constitute little more than a visual traffic separator. They do not constitute a barrier to encroachment of vehicles into oncoming traffic lanes and, when struck by a vehicle, could be projected into lanes of moving traffic.
Other solutions, such as shown in U.S. Pat. Nos. 3,391,620 and 4,004,857 involve the movement of lightweight barriers transversely across the roadway from one lane divider to another. However, such systems require that modifications be made to the roadway and are, therefore, relatively expensive. Moreover, such lightweight barriers do not constitute a substantial barrier to head-on collisions and may, themselves, cause damage if struck by an automobile.
Another system, shown in U.S. Pat. No. 3,958,890 provides for the movement of heavy, substantial divider sections transversely across the roadway, but such system requires the permanent installation of crossbeams supported on columns which, in turn, support the hoists required to lift the sections. Other systems requiring permanent and expensive installations are shown in U.S. Pat. Nos. 2,182,697 and 2,287,685.
A transfer vehicle for moving a chain of units forming a "center-line" is shown in U.S. Pat. No. 2,931,279.
In our previous U.S. Pat. No. 4,474,503, we proposed a traffic barrier that comprises a chain of relatively heavy sections hinged together. A transfer vehicle includes trolley wheels that lift the barrier, section by section, and move it diagonally across the vehicle to deposit it along the next adjacent lane divider. Such apparatus appears to be workable for straight roadways, but serious problems would be encountered on curved roadways where the lane dividers around the curve are of different arcuate lengths. That is, for each unit of distance traversed by the vehicle, it would normally deposit the same length of barrier as it picks up, whereas on a curved roadway, the length of barrier required to be deposited may be shorter or longer than that picked up.